In the field of electrical to electrooptical energy conversion, the integrated array of light emitting diodes has many benefits. However, thus far in the art, while the techniques of forming devices in an integrated array are well developed, substantial difficulty has been encountered in providing some degree of color selectibility, and hence variation in the frequency of the electromagnetic energy output, in the integrated array. Integrated structures wherein the principle of achieving different colors by forming the diodes at a specific place in a concentration gradient of semiconductor material are available in the art such as the teaching in U.S. Pat. Nos. 3,873,382 and 3,725,749. However, these patents are directed to relatively complicated process steps.